Star map



Nov. 1, 1938. c, M T N 2,135,287

STAR MAP I Filed March 7, 193a WESTERN HORI20IV IN VEN TOR.

ATTORNEY Patented Nov. 1, 1938 UNITED STATES PATENT OFFlJCE I STAR MAPClaude M. Houston, Pittsburgh, Pa. Application March 7, 1936, Serial No.67,652

10 Claims.

This invention relates to hemispherical star maps.

One of the objects of this invention is to provide a star map in whichvarious star groups and positions are shown exactly as they appear tothe eye of the observer who views. the sky facing any horizon.

Another object of the invention is to provide a star map in whichdistortions and inaccuracies, always present when showing a spherical.area on a plane surface, are eliminated;

Yet another object of the invention is to provide a hemispherical starmap in which the concave hemispherical area is manually adjustable torepresent the visible sky at the desired hour of the day or night forany time ofthe year.

Still another object of the invention, asv a manufacturing sequence, isto depict a star map on the outer surface of a spherical body, made ofthin elastic material, collapse the same so as to form a hemisphere orbowl with a double wall in which approximately one half of the outersurface of the spherical body forms a convex surface of thehemispherical double walled bowl and the remaining half forms the innerconcave surface of the bowl which latterv surface shows the star map tobe viewed by the observer.

Another object of the invention is to provide a hemispherical star map,having the shape of 30 a bowl, which is folded along a great circle lineof the original hollow sphere and in which the edge or rim (great circleline) represents the horizon of the concave surface of the star mapshowing the visible sky.

Yet another object of the invention is to provide a hemispherical star'map with a mechanical member inserted between the double walls of thebowl which efiects pivoting of the star map about polar points as itmoves relatively 40 between these walls of the bowl representing thevisible sky and which indicates the hour of the day or night for anytime of the year corresponding to the position of the sky which isrepresented within the bowl as then visible on the star map.

Still another object of this invention is to provide a hemisphericalstar map which can be folded intoa small volume without injury and whichcan be carried in the pocket or can be placed in a small receptacle,when not in use.

Other objects and advantages of the invention to be derived from the useof my improved hemispheri'cal star map will appear from the followingdetail description of the accompanying drawing, in which:

Figure: l isa sectional view of a hemispherical star map embodying myinvention along line l--| in Figure 2,

Figure 2 is a fragmentary outline view of the invention. 5 Figure 3 isaperspective view of the invention. Figure 4 is a; side elevation of: themember which eflects" pivoting of the star 'map. about a polar point.

Figure 5 is a top view' of Figure 4'. 10

, Ordinarily-,star maps used by amateur astronomers areprinted on aplane surface, such as cardboard or'paper', and in this: state it. isvery difficult tostudy the stars, due to distortions and inaccuracies;which occur when attempting to 15 depict a spherical area on a planesurface. These disadvantages have been eliminated by producing'a starmap which shows the star groups exactly as they appear to the eye of anobserver who views the sky facing any horizon. I attain this end by thefollowing steps of manufacture.

Upon the outer surface of a hollow spherical body N1, of thin andflexible sheet rubber (or any other, suitable material), is depicted thepositions of the principal stars andconstellationsas they appear in theapparent concave spherioalsurface of the heavens surrounding the earth.These star groups are located on the outer-surface of the sphere, not asan observer 30 from outsideof the apparent stellar system would see themwhen looking toward the earth, but according to a mirror image of thatview. In other words, the star groups are located on the outside surfaceof the sphere in relations to the 35 celestial meridians and parallels,just as an observeron the earth" would see them when looking atthe-inside surface of the celestial sphere of the heavens.

The next step of manufacture is to collapse the hollow sphere into adouble-walled bowl or hemisphere, as shown in Figures 1, 2 or 3 of thedrawing.

'The north polar point (North Star) is 40 from 1 In Figure l, the northpolar point is thehorizon, on the inside of the bowl.

'Thesouth polar point of the original sphere is now on the outside,surface of the ,bowl, and also 405 from the rim of the bowl.

indicated by: l6 and the south polar point is indicated In changing thestar map picture shown on the inside ofthe bowl, it will "be seen thatthe location of. the north-and south polar points must always be kept inthe same place and the 'walls of the bowl must be manipulated so asytoi1 bring new areas from the outside surface to; the

inside surface of the bowl, and vice versa, areas now shown on theinside of the bowl will be moved around over the rim to theloutside of'the'bowl (except those ,circumpolar stars within 40 of the North Pole,which merely swing around the pole point, always on the inside of thebowl). "In mylstar map device,these movements are imposed and regulatedby'means of a narrow, flat lineally curved strip I I, (about 100 arclength for .40 latitude maps) located between thewalls of the bowl, andhaving pivot pins and I3 extend- 1 ing thru the walls; pivot I 4 extendsthru the inner wallfat thenorth polar. point while' pivot-l3 ex tendsthru'thefouter wall atlthe south polar point. Strip I l is inserted intothe interior thru a-slit' in '80 V inside (star map) surface of thebowl, i.'e. the slit the outer wall surface which never appears on theis within of are from the south'polarpoint;

After strip II is in proper position,'-the-Nor th Pole pivot pin l4isriveted over, as' toform' head IQ of Figure 4, thus retaining it atthe north polar point of the star map.- -Similarly, South 'Pole pivotpin l 3 is fastened in'position, but South Pole pivot pin l3 has rigidlyattached to itself the circular dial20, justoutside'of the wall of thebowl. Circular .dial 20 has printed on its peripheral edge, the names;of the months 2| "The months can be further graduated into days if'deisired. On the outer'surface' of the'bowl, in close proximity to theperipheryof said dial 20, is printed the hours 22 0f the day-and night,as best shown in Figure 2. Allof these'index markings and devices ontheoutside surfacepare 'within' an area never appearing on the inside-(star map) surface of the bowl, ifeithey are wi thin 40 of are "fromthe south polar point, Any otherdata, in-

structions or information can also be printed 'on this same outer areaif desired.

Before' rigidly fastening circular dial 20 to the pivot pin I3, care is'taken, of course, to have the month and day' markings 11 on. itsperiphery, match the hourlyfigures 22-0n the outer bowl'surface, tocorrectly indicate the sky map which is then in view onthe"insidehemispherical sur face of the bowl. 7

' This essentially completes the steps in'the'manufacture of the deviceand the star mapis now ready for: use. 5

As depicted in Figure 3, the star map there shown is set to observe onthe inner hemispherical surface 24 ofthe bowl 23, the positions of thevarious star groups asl'they'appear' to an observer-on the montlnday'and hour as indicated by the dial in conjunction, with the imprintedhours on the outside of the'bowl, for instance the dial asshown, is:.nowset to observethe. star groups for the middle of December awe'oo PLM.

or for the end of August at 2600A. M. or for the beginning of April at12:00 noon, (the sun, of

course, makes the stars invisible at 12:00 noon, 7

but the star map shows the location of them in the heavens at thattime).

The user of the star map need only remember that the insideof the bowlrepresents, in'miniature, the apparent celestial bowl of, the naturalskywhich he sees overhead and down to the n horizon. Thus if he'facesnorth and,'preferably; f

for a'beginner, holds the star map bowl over head or above eye level,with the north horizon rim' pointingin the northerly direction, then theiden in facing any other horizon, as for instance, the western horizonshown in the sectional view of Figure;l the map is held with the westernhorizon rim toward the west and the bowl shows the stars then visible tohim in the heavens from the westernhorizon to the zenith. And in everycase, the star groupsare shown. on the star map bowl exactly in the sameaspects andrelations to other looking .at. the natural heavens. This is.the unique feature of my star. map, theonlystar map which can boastofshowing thestars at all times and in all portions of thevisibleheavens,

"just as they actually appear to an observer on the earthy. vThisfeature'cannot otherwise be obtained except in the elaborate complicatedand costly mechanisms of planetarium devices inside large dome shapedrooms, as the Hayden Planetarium in. New York city or the AdlerPlanetarium in.

Chicago. 2

- -And incidentally; my invention is also adaptable flli' V i to largescale'construction to operate as the hemi spherical dome of a largecircular room (as-the planetariums) within which audiences can gath erand watch accurate. reproductions of the motions of the stars in theirtraverses across the sky.

- Now, to change the star map picture, (suppose,

forexamplait'is desired to show the sky at 9:00

visible starsan'dgroups" as he sees them when on August 1st instead ofat 3:00 A .*M.

August 1st as is now shown on the drawing:

. The'bowl, as in Figure 2 or Figure 3, is'grasped with the thumbs andfingers of each hand, thumbs inside. the. bowl and fingers on theoutsidejof the bowl. near opposite edges of the rim or horizon line; forinstance, the right thumb might touch at Gemini and the left thumb atCygnusfiFigure 2.or 3; manipulate thumbs and fingers inop-.

posite directions, slidingthe two walls of the bowl past each otherbetween each thumb and finger;

so as to simultaneously roll the outer wallof the bowl overthe horizonrim' to the inside of the bowl at'the right side, and, vice versa, rollthe inner wallof the bowl over the horizon rim to the 7 .Thesecomoutside of the bowl on the left side.

plementary movements must take place because I of the pivoting actionthe walls are forced to make 7 around pivot pins l4 and l3.

The northern zone star groups will move in a counterclockwise I circlearound the North Pole' pointas a center; new star groups will come -overthe eastern horizon (right side) andappeanon the inside of the bowlthere the' formerly visible stars will disappear over the westernhorizon (left side), just as the stars rise and set in the natural sky.Continue the movement, glancing at'the index, until the hour figure 9 ofthe the dial index; and then the star groups shown on the inside-of thebowl will be those visible in the natural sky on August'lst at 9:00oclock P. M.

7 Similarly, for any other time of the year, at any Night? arc comesopposite the word August on 1 to t hour of the day or 'nig'ht,?theinvention canbe altered and set to show on the interiorof -the bowl thestarswhich are visible in the natural heavens at that time.

Observation of the movements-on the inside :of the bowl as themappicture-is changed, will show that the invention reproducesaccurately 'and without distortion the true appearance and :movement ofthe stars in the sky, theirrrising,

their traverse in arcs across thesk-y, and their setting, showingcorrectly their altering aspects irrespective of whether shown near anyhorizon orlhigh up in the sky. 'lhatfeatureis something no flat star mapdoes nor-can 'do,which'isthe reason that amateur or lay star s'tudents'cannot "recognize and identify near-"horizon constellationsfromthe'usualstar maps. A constellation will lie on its left side whenrising (eastern-horizon) :and lie on its right side when setting(westerh horizon); the two aspects "are verydiiferent to an observerstanding on the earth looking at them, and both aspects again differfrom the appearance when the constellation is high lin the sky near themeridian, which is how theusual flat star map depicts them.

My star map always shows the star groups in aspects just as theyactually appear to an observer on the earth, irrespective of in whatportion of their celestial traverse they are located.

My star map device is adaptable to satisfactory use at any place on theearths surface. As has been mentioned, the figures shown on the drawing,depict a star map which is about correct for the 40th north geographicalparallel of the earth, or the approximate latitude of Pittsburgh, Pa.,or Madrid, Spain, or Peiping, China. For all practical purposes ofpopular use, this map would be sulficiently correct for a parallel zonecovering degrees or degrees of longitude. However, in Alaska or inMexico, say a different curved strip H would be used; strip ll would beshorter for Alaska to bring the North Pole higher up in the sky towardthe zenith; while for Mexico, strip 1 i would be longer to bring theNorth Pole lower in the sky toward the horizon.

For the southern geographical hemispheres as South America, South Africaor Australia, the

vSouth Pole pivot I3 is the one that is inside the bowl and the NorthPole point I4 is outside of the bowl and it is the North Pole pivot pinwhich then carries the index dial 201.

It is possible to design my star map device so that different curvedstrips II can be furnished and assembled by the user, to fit one starmap for practically any latitude it is desired to use it. However, it ispreferable to manufacture a map for only one suitable zone of latitude,and to use different star maps for any other zone differing greatly inlatitude.

While I have illustrated and described my invention, I do not desire tobe limited to the structural details so illustrated and described; butintend to cover all forms and arrangements which fall within the termsemployed in the definitions of my invention constituting the appendedclaims.

I claim:-

I. As an article of manufacture, a star map comprising a hollowspherical body of resilient material collapsed into the shape of adouble walled hemispherical bowl, and a star map depicted on the surfaceof said spherical body.

2. As an article of manufacture, a star map comprising a hollowspherical body of resilient material collapsed along a variableequatorial rbending .line "into "the shape of a hemispherical;bowl:and:a star ;map depicted on 17118 1111181 con- -:cave:sur'face ofsaid bowl.

;3.,As:-,an..artic1e:of manufacture, a star map :nomprising a vhollowspherical :body of resilient smaterial collapsed along a variableequatorial :b'ending Llinezinto the shape of a double walledtbowllandastar :map originally depicted on the ,outerssurfacelof saidspherical :body and arranged L170 :appearon nthe inner concave surfaceof said bowl.

.4. As an :article of manufacture, a star map -.comprising a hollowspherical body of resilient fm'aterial collapsed along a variableequatorial 'ben'ding :lineinto .the shape of a double walled bowl, astar map depicted on the inner surface of said bowl and means todefinesaid equatorial Ebending line.

As an article of manufacture, a star map icomprising 'arhollow spherical.body of resilient material collapsed along a variable equatorial"bending line into the shape of a hemispherical ;double'wa1led=bowl, astar map depicted on the inner .concavesurface of said bowl :and adjust-:aablemeansto define said equatorial bending line relative a selectedchronical period.

6. As an article of manufacture, a star map comprising an initiallyhollow spherical body of resilient material collapsed along anequatorial bending line into the shape of a double walled hemisphericalbowl; a star map positioned on the inner concave surface of said bowl,and an arcuate member pivotally mounted between the walls of saidhemispherical bowl to define said equatorial bending line.

7. As an article of manufacture, a star map comprising an initiallyhollow spherical body of resilient material collapsed along anequatorial bending line into the shape of a double walled hemisphericalbowl; a star map depicted on the inner concave surface of said bowl; anarcuate member pivotally mounted at its ends between the walls of saidhemispherical bowl to define said equatorial bending line; an indicatordisc secured to one of the pivots of said member and positioned insubstantial parallel relation to and outwardly of the outer convex faceof said hemispherical bowl; another indicator in concentric relationwith the said disc depicted on said outer convex face, one of saidindicators bearing the names of the months in spaced relation and theother indicator being graduated to indicate the hours of the day.

8. As an article of manufacture, a star map comprising an initiallyhollow spherical body of resilient material collapsed along anequatorial bending line into the shape of a double-walled hemisphericalbowl; a star map originally depicted on the outer surface of saidspherical body and arranged to appear on the inner concave surface ofsaid bowl; an arcuate member located between the inner and outer wallsof said doublewalled bowl, said arcuate member carrying pivots fixingthe locations of the polar points and adapted to define said equatorialbending line and indicator means to position said arcuate member andsaid bending line relative to a selected chronical period.

9. As an article of manufacture, a star map comprising an initiallyhollow spherical body of resilient material collapsed along anequatorial bending line into the shape of a double-walled hemisphericalbowl; a star map originally depicted on the outer surface of saidspherical body and appearing on the inner concave hemispherical surfaceof/ said bowl, the constellations depicted on said star map alwaysappe'aring'in the same aspect as the natural constellations in thenatural sky at all positions of their traverse across the'visibleheavens; an arcuate member 'pivotally mounted betweenthe inner and outerwalls of said double-walled bowl, said arcuate r'nemberprovided withpivots adapted to fix the location of the polar points and kinematicallyiimiting'the motion of the map walls to circular swings around saidpolar points as centers, in exact reproduction of the apparent motionsof the natural sky about the celestial polar axis and 1 indicator meansto position said arcuate member apparent bowl of the natural sky as seenby an observer on the earth; a star map depicted on the inner concavehemispherical surface of said bowl, the constellations on said star mapalways ap- 'pearingrin thesameasp'ect as the natural constellations in.the natural sky at all portions of their traverse across the, visibleheavens; an arcuate member located in the space between the inn-er andouter walls of said double-walled bowl,

said arcuate member carrying pivots fixing the locations of the polarpoints and kinematically limiting the motion ,of the Vmap Walls tocircular swings around'the polar points as centers, in exactreproduction of the apparent motions of the natural sky about thecelestial polar axis; an indi'- cator disc secured to one of the pivotpins of said arcuate member and positioned in substantial parallelrelation to and outwardly of'the convex outer surface of saidhemispherical bowl; another ,15 indicator depicted on said outer convexsurface 7.

in concentric relation with said disc; one of said indicators bearingthe names of the months and the; other indicator being graduated toindicate the hours of the day; means allowing the map area to be changedat will so as to depict in turn the complete cycle of sky panorama foreach hour, day and month throughout the astronom-f ical year. 7

- CLAUDE M. HOUSTON.

